Here is what happened to me:
I set up the SoX resampler in Foobar to upsample everything to 96K except for 88.2 files and 96 files. Everhting played fine until I played a native 24/88 file from Linn Records. It played fine but last time I played it with the Musiland it sounded much better.
So I deactivated all DSP plugins and the file still didn't sound good.
Up to that point my assumptions were:
a) There was some resampling going on specifically on the 88.2 files
b) The clock was poorly generated for 88.2K frequencies
c) a little of both a) and b)
Then I checked the control panel of the Teralink X2 and it showed 24/96 while playing different 24/88. So I got even more suspicious. The control panel showed correctly the 44.1, 48 and 96 frequencies but not the 88.2.
Then when you talked about having a DAC which displays sample rates, it made me remember that the control panel of the emu 0404 usb had that function: it displays the digital input sample rate.
So finally I repeated the test with Emu 0404 usb and it confirmed what I suspected: 44.1, 48 and 96 are played fine but not 88.2 which is resampled to 96.
Overall, it is not a big problem for me but I thought it was worth mentioning it. For now I have set the SoX upsampler to upsample everything to 96K and the SoX plugin does sound better than the software upsampling that seems to be going on with the Teralink X2.
Have you had a chance to compare 44.1 upsampled to 48khz via the TerralinX vs the Hiface at 44.1? I still have an X1 but you almost have me convinced on the Hiface, I propose overly critical possible design issues with products before I buy something because I'm a cheapstake and need to know the + and -'s of a product before the purchase (a bit OCD as my wife says).